SRM 584 Div2 500

Egalitarianism.java

import java.util.LinkedList;
import java.util.Queue;

public class Egalitarianism {

  public int maxDifference(String[] isFriend, int d) {    
    int mmax =  0;
    for (int s = 0; s < isFriend.length; s++) {

      Queue<Integer> queue = new LinkedList<Integer>();
      int[] step = new int[isFriend.length];
      boolean[] visited = new boolean[isFriend.length];
      
      queue.add(s);
      visited[s] = true;
      step[s] = 0;
      while (!queue.isEmpty()) {
        int q = queue.poll();
        for (int i = 0; i < isFriend.length; i++) {
          if(q == i) continue;
          if(isFriend[q].charAt(i) == 'Y'){
            if(!visited[i]){
              queue.add(i);
              visited[i] = true;
              step[i] = step[q] + 1; 
            }
          }
        }
      }
      
      for (int i = 0; i < visited.length; i++) {
        if(!visited[i]){
          return -1; 
        }
      }
      
      int max = 0;
      for (int i = 0; i < step.length; i++) {
        if(step[i] > max){
          max = step[i];
        }
      }
      mmax = Math.max(max, mmax);
    }
    return mmax * d;
  }
}